1. Field
Exemplary embodiments of the invention relate to a washing machine and a method of controlling the washing machine.
2. Background
In general, a washing machine is designed to wash the laundry using emulsification of a detergent, a water stream action generated by the rotation of washing blades or washing tub, and an impact action applied by the washing blades. The washing machine performs washing, rinsing, and/or spinning to remove contaminant from the laundry by using an action between water and the detergent.
The washing machine includes a tub for storing the water and a drum that is rotatably provided in the tub and in which the laundry is loaded. The tub is disposed such that it is suspended from an inner top of a casing that is referred to as a main body, a cabinet, a casing or the like that defines the appearance of the washing machine. In order for the tub to be suspended from and be supported by the inner top of the casing, a tub supporting member connecting the tub to the casing is provided.
A washing machine may detect a laundry load, after which it performs the washing, rinsing, or spinning in accordance with a preset pattern depending on the detected laundry load. The laundry load detection is performed in an indirect method based on a rotational property of a pulsator that varies in accordance with the laundry load.
For example, when the pulsator rotates in a state where the laundry is loaded in the drum, the load applied to a driving unit driving the pulsator is relatively high in a relatively large amount of laundry load. On the contrary, in a relatively small amount of laundry load, the load applied to the driving unit is relatively low. Therefore, the rotational property of the driving unit may vary in accordance with the laundry load and thus the laundry load may be detected in accordance with the rotational property.
However, because the above-described method is an indirect method in which the rotational property of the pulsator is observed and the laundry load is assumed based on the observed rotational property, it is impossible to accurately measure the laundry load. Likewise, the accuracy of detection of a degree of unbalance of the laundry is deteriorated.
For example, when the laundry gets tangled in the drum, the rotation of the pulsator cannot be smoothly realized even when a small amount of the laundry is loaded in the tub. Therefore, it may be erroneously detected that a large amount of the laundry is loaded. In addition, when wet laundry is loaded in the drum, the measured laundry load may appear greater in comparison to the same load, if that load was dry. Therefore, there is a need to devise a method that can more accurately detect the laundry load.
FIG. 15 is a washing machine according to the prior art. The washing machine includes a casing 1 defining an appearance of the washing machine, a water tank (or tub) 2 disposed in the casing 1, and a drum 3 that is rotatably provided in the tub 2. A pulsator 4 is provided under the drum 3. The drum 3 and the pulsator 4 are connected to and driven by a vertical washing shaft 13a connected to a driving unit 13.
The casing 1 is formed in a rectangular parallelepiped box shape and provided with a door through which the laundry is loaded and unloaded. The tub 2 is formed in a cylindrical shape having an opened top and suspended in the casing 1 by a supporting member 152.
The supporting member 152 may be provided with a load cell 220. The load cell 220 is a sensor that can detect weight using tensile force. The load cell 220 is illustrated in an enlarged state in a circled portion of FIG. 1. In FIG. 1, the supporting member 152 is divided into upper and lower bars 152a and 152b and the load cell 220 may be mounted between the upper and lower bars 152a and 152b. 
As illustrated in FIG. 15, in order to effectuate the coupling of the supporting member 152 to the load cell 220, an end portion 152c of the upper bar 152a is bent and connected to the load cell 220. However, in this configuration, vibration generated by the rotation of the drum 3 is transferred to the bent end portion 152c and acts to unfold the bent end portion 152c and thus the coupling of the supporting member 152 and the load cell 220 may be released.
Alternatively, a screw thread (not shown) may be formed on an end portion of the upper bar and screw-coupled to the load cell. However, in the prior art, the screw threads in the upper and lower supporting bars have the same direction, in such a configuration, the screw-coupling may be released by a rotational force transferred by the rotation of the drum 3.